1. Field of the Invention
The invention relates to the beneficiation of phosphate ores, and especially to an improvement that allows flotation of deoiled rougher concentrate in the amine circuit without prior washing.
2. Discussion of the Prior Art
Flotation is exclusively used in the concentration of phosphate ores, and given the very great differences in the various properties of the important constituents, flotation gives definite advantages over other types of separation.
Beneficiation of phosphate ores by flotation, as with other ores, is primarily concerned with the separation of one mineral from another by floating one away and leaving the other suspended in the water. This is made possible by selective use of organic or inorganic reagents which will render one or more of the ore constituents nonwettable, thereby allowing it to be held at the water surface by surface tension forces.
In the present system of phosphate rock flotation, the final grade of concentrate is achieved through a two-stage separation. Following the removal of slimes and other components that can be removed in the initial washing, the phosphate rock is treated, for example, with a fatty acid-fuel oil reagent system in an alkali solution. The float from this stage, the rougher concentrate, is normally de-oiled, washed and treated with amine and kerosene for a second float. The product has a resulting final concentrate (sink) grade of 72-78% bone phosphate of line (BPL).
Until now, there has been an unavoidable need to wash the deoiled rougher concentrate prior to the amine float. The present invention eliminates this need.